The present invention relates to absorbent articles such as diapers, incontinent briefs, diaper holders, and the like, and more particularly, to absorbent articles having elastic waist features providing dynamic fit about the wearer as well as improved containment characteristics of the absorbent article.
Infants and other incontinent individuals wear absorbent articles such as diapers to receive and contain urine and other body exudates. Absorbent articles function both to contain the discharged materials and to isolate these materials from the body of the wearer and from the wearer""s garments and bed clothing. Disposable absorbent articles having many different basic designs are known to the art. For example, U.S. Pat. No. Re. 26,152, entitled xe2x80x9cDisposable Diaperxe2x80x9d issued to Duncan and Baker on Jan. 31, 1967, describes a disposable diaper which has achieved wide acceptance and commercial success. U.S. Pat. No. 3,860,003, entitled xe2x80x9cContractable Side Portions For Disposable Diaperxe2x80x9d, issued to Buell on Jan. 14, 1975, describes an elasticized leg cuff disposable diaper which has achieved wide acceptance and commercial success.
However, absorbent articles have a tendency to sag or gap away from and to slide/slip down on the body of the wearer during wear. This sagging/gapping and sliding/slipping is caused by the relative motions of the wearer as the wearer breathes, moves and changes positions, by the downward forces generated when the absorbent article is loaded with body exudates, and by the deformation of the materials of the absorbent article itself when subjected to such wearer""s motions. This sagging/gapping and sliding/slipping of the absorbent article can lead to premature leakage and poor fit of the absorbent article about the wearer in the waist regions and the leg regions of the absorbent article.
In order to more snugly fit absorbent articles about the waist of the wearer, certain commercially available absorbent articles have been provided with elastic waist features. An example of a disposable diaper with an elastic waist feature which has achieved wide acceptance and commercial success is disclosed in U.S. Pat. No. 4,515,595 issued to Kievit and Osterhage on May 7, 1985. Elastic waist features will typically comprise an elasticized waistband consisting of an elastic member contractibly affixed between the topsheet and the backsheet. The elasticized waistband is, thus, designed to expand and contract with the wearer""s motions and to maintain the fit of the absorbent article about the waist of the wearer during use (i.e., provide sustained dynamic fit).
However, it has been found that absorbent articles having elastic waist features also have a tendency to sag/gap and slide/slip during use. Further, the elastic waist feature has a tendency to rollover or roll-in at the front of the diaper resulting in a lack of fit about the waist of the wearer.
Thus, it would be advantageous to. provide an absorbent article having an elastic waist feature that provides better fit, reduced leakage, and wearer comfort. It would further be advantageous to provide an absorbent article which has reduced sagging, gapping, rollover, or roll-in at the waist of the diaper as well as reduced overall sliding/slipping of the absorbent article or the absorbent core on the wearer during use.
Therefore, it is an object of the present invention to provide an absorbent article having sustained dynamic fit about the waist of the wearer during use.
It is a further object of the present invention to provide an absorbent article having a unique elastic waist feature that provides sustained dynamic fit and improved resistance to leakage during use.
It is a still further object of the present invention to provide an absorbent article having a unique elastic waist feature which reduces sagging, gapping, rollover or roll-in at the front of the diaper as well as overall sliding/slipping of the absorbent article or the absorbent core during use.
It is an another object of the present invention to provide a unique elastic waist feature having an elasticized waistband that provides such sustained dynamic fit by providing a predisposed, resilient, waistband flexural hinge zone which allows relative flexural bending between zones of the elasticized waistband and provides a restoring force/moment to resiliently return the zones to essentially their preceding in-use configuration.
It is a further object of the present invention to provide a closure system that maintains/creates lateral tension through at least a portion of the unique elastic waist feature to enhance the sustained dynamic fit.
These and other objects of the present invention will be more readily apparent when considered in reference to the following description and when taken in conjunction with the accompanying drawings.
The present invention provides absorbent articles such as disposable diapers, incontinent briefs, diaper holders and the like, that have a unique elastic waist feature that improves the dynamic fit of the elasticized waistband as well as the containment characteristics of the absorbent article. Such absorbent articles comprise a containment assembly preferably comprising a liquid pervious topsheet, a liquid impervious backsheet, and an absorbent core positioned between the topsheet and the backsheet; an elastic waist feature; and a closure system for creating/maintaining lateral tension through at least a portion of the elastic waist feature.
The elastic waist feature preferably comprises an interconnecting panel zone, a first flexural hinge zone joining the interconnecting panel zone with the containment assembly, an elasticized waistband, and a second flexural hinge zone joining the elasticized waistband with the interconnecting panel zone. The elasticized waistband comprises a shaping panel zone; a waistline panel zone; and a predisposed, resilient, waistband flexural hinge zone joining the shaping panel zone and the waistline panel zone. The interconnecting panel zone provides a flexible link between the elasticized waistband and the containment assembly to allow rotations and translations of the elasticized waistband so that the elasticized waistband may move in functional contacting position and conform with- the waist of the wearer. The elasticized waistband is designed to elastically expand and contract and to dynamically fit the wearer""s waist. The waistband flexural hinge zone is predisposed to allow the panel zones to flexurally bend about a defined axes or zone and is resilient to provide a restoring force/moment that returns the panel zones to their preceding in-use configuration, especially when the elasticized waistband has been pretensioned by the closure system. Thus, the elastic waist feature moves with and conforms to the waist of the wearer as the wearer sits, stands or moves. The elasticized waistband preferably comprises a portion of the topsheet, a portion of the backsheet that is preferably prestrained, an elastomeric member, and a resilient member that enhances the resiliency for the waistband flexural hinge zone.
The absorbent article is also preferably provided with a closure system (tensioning means) for dynamically creating/maintaining lateral tension through the elasticized waistband. The lateral tension dynamically created and maintained by the closure system xe2x80x9cactivatesxe2x80x9d the stretch of the elasticized waistband thereby allowing it to more dynamically expand and contract with the motions of the wearer. The closure system preferably comprises a dual tension fastening system. The dual tension fastening system comprises a primary fastening system for forming a side closure and a waist closure system for forming a waist closure. The primary fastening system maintains the first waist region and the second waist region in an overlapping configuration such that lateral tensions are maintained around the circumference of the diaper to maintain the diaper on the wearer. The primary fastening system comprises a securement member, preferably a tape tab and a first fastening component, and a landing member preferably comprising a second fastening component to provide a variable positioning side closure. The waist closure system forms a waist closure that anchors a portion of the end edge of the absorbent article and that dynamically maintains/creates lateral tensions through the elasticized waistband so as to improve the fit and containment characteristics of the diaper by reducing gapping, sagging, and rollover of the elasticized waistband. The waist closure system comprises at least one, preferably a pair of, first attachment component(s) longitudinally aligned with the elasticized waistband and at least one second attachment component. Each attachment component comprises a fastening means that engages a complementary fastening means for providing a variable positioning, passively activated, waist closure. The first attachment component(s) preferably comprise a hook fastening material while the second attachment component preferably comprises a loop fastening material.
In an especially preferred embodiment of the present invention, the absorbent article additionally comprises a pair of elasticized side panels disposed in the second waist region. The elasticized side panels provide an elastically extensible feature that provides a more comfortable and contouring fit by initially conformably fitting the diaper to the wearer and by sustaining this fit. The elasticized side panels further develop and maintain wearing forces (tensions) that enhance the tensions developed and maintained by both the primary fastening system and the waist closure system. The elasticized side panels especially assist in pretensioning the elasticized waistband and further provide more effective application of the diaper. While each elasticized side panel may be constructed in a number of configurations, the elasticized side panel preferably comprises a xe2x80x9czero strainxe2x80x9d stretch laminate. The elasticized side panel also preferably has an extension panel adjacent the leg of the wearer so that tensional forces through the side panel are not concentrated so as to prevent the indentation, rubbing, or chafing of the wearer""s skin during use.
The present invention also relates to alternative elastic waist features comprising an xe2x80x9cexpansive tummy panelxe2x80x9d elasticized waistband. In these embodiments the elasticized waistband is capable of expanding well beyond the dimensions of the absorbent article set by the primary fastening system (beyond the planar state of the diaper itself) so as to accommodate wearers, especially large infants, with large expansile waists so as to reduce the sagging/slipping of the absorbent article. The extension forces of the elasticized waistband are lower than the extension forces of the elasticized side panels so as to accomodate such expansion. In a preferred embodiment of this elastic waist feature, the elasticized waistband is formed from a stretch laminate. The stretch laminate is comprised of an elastomeric member and a portion of the topsheet and the backsheet which all have been mechanically stretched. In a preferred embodiment, the waistline panel zone is formed by removing a portion of the backsheet (windowing). The shape of the elasticized waistband also provides differential extensibility in the lateral direction.